A solar cell module is one of the most important components of a solar power generation device. Sunlight irradiates onto a cell from its front surface and is converted to electricity within the cell. Primary grid lines and secondary grid lines are disposed on the front surface, and then a welding strip covering and welded on the primary grid lines outputs the current. The welding strip, the primary grid lines and the secondary grid lines cover part of the front surface of the cell, which blocks out part of the sunlight, and the part of sunlight irradiating onto the primary grid lines and the secondary grid lines cannot be converted into electric energy. Thus, the welding strip, the primary grid lines and the secondary grid lines need to be as fine as possible in order for the solar cell module to receive more sunlight. However, the welding strip, the primary grid lines and the secondary grid lines serve to conduct current, and in terms of resistivity, the finer the primary grid lines and the secondary grid lines are, the smaller the conductive cross section area thereof is, which causes greater loss of electricity due to increased resistivity. Therefore, the welding strip, the primary grid lines and the secondary grid lines must be designed to achieve a balance between light blocking and electrical conduction, and to take the cost into consideration.